One common type of agricultural combine includes a transverse rotating cylinder with rub bars arranged on an outer surface thereof. The cylinder is mounted on a shaft and a cylinder drive typically comprises a pulley or sprocket on one end of the shaft that is driven by suitable belts, chains, or the like. The outer surface of the cylinder rotates in relatively close proximity to a concave grate located generally under the cylinder, and typically an adjustment mechanism is provided to vary the clearance between the rub bars and the grate. Typically as well, this clearance decreases from the front of the grate to the rear of the grate. The cylinder rotates in a forward direction such that the bottom thereof moves rearward, and crop material is fed from the combine's feeder mechanism into the front of the cylinder and passes between the rub bars on the cylinder and the grate to rub the desired seeds out of the crop material. The desired seeds pass through the grate and are collected in the combine while the balance of the crop material passes through the combine back onto the field.
A common problem with combines is that crop material will sometimes jam between the cylinder and the grate, causing the cylinder to stop rotating. The crop material enters the front of the grate where the clearance between the cylinder and grate is greatest, and as it moves rearward and the clearance decreases, the crop material can jam, either when the crop material is damp, or when the crop material enters in a wad or lump. The crop material must be then be cleared from the area between the cylinder and the grate before harvesting can proceed. Typically to clear the crop material, the grate is moved downward to increase the clearance between the cylinder and grate to the maximum clearance available. The cylinder is then rotated in a reverse direction such that the bottom of the cylinder moves forward with respect to the grate, and the crop material moves forward from the low clearance area at the rear of the grate to the higher clearance area at the front of the grate where it loosens and can be manually removed through an access port typically provided on the combine.
In order to rotate the cylinder in the reverse direction, combine operators typically use a lengthy bar with one end adapted such that the operator can engage the bar with the cylinder shaft directly with a wrench type end, or via the pulley or sprocket mounted on the shaft by engaging the bar in corresponding apertures spaced around the pulley or sprocket. The operator then manually exerts a force on the outer end of the bar, where leverage is maximized, to rotate the cylinder in the reverse direction. In most cases, significant force is required to rotate the cylinder. Typically the operator orients the bar, if room allows, such that same extends rearward and upward relative to the cylinder shaft, and the operator pulls down so that his weight is added to the force on the bar. Pulling downward on the bar extending rearward from the cylinder shaft exerts a force that moves the bottom of the cylinder forward in the reverse direction. Combine configurations vary greatly such that the location of the cylinder pulley often does not allow the bar to oriented conveniently and the operator is thus required to pull up or laterally on the bar, sometimes in an awkward position where it is difficult to pull effectively.
Often the operator will be unsuccessful in moving the cylinder, and then must enlist further help in order to rotate the cylinder, or attempt to dig the material out through the front end of the grate. Frustration with failed attempts to reverse the cylinder can lead the operator to take hazardous steps such as standing and jumping on the bar which can cause the bar to slip out of engagement with the cylinder and injure the operator. Often attempts are made to engage an extension on the bar to increase the leverage, however clearance is often limited. A jammed or plugged cylinder is generally regarded as one of the most distasteful occurrences a combine operator can encounter, requiring considerable time and effort to clear.
Agricultural combines are also known that have a longitudinally oriented rotor and grate, analogous to the cylinder and grate described above, and similar jamming is known to occur in these rotary type combines.
Combine feeder reversers are known comprising a motor operative to turn the feeder mechanism in a reverse direction in order to clear jammed crop material from the feeder house, however such mechanisms have not been adapted to reverse the cylinder or rotor because the force required to reverse the cylinder is much greater than that required to reverse the feeder and suitable motors and drives have not been known.